Polymers & Resins Available — Bulk Only

Low-Viscosity HDI Trimer Polyisocyanate

CAS 28182-81-2

Low-viscosity HDI trimer is an aliphatic polyisocyanate resin based on the isocyanurate (trimer) of hexamethylene diisocyanate (HDI), formulated for reduced viscosity. It serves as the hardener in high-solids, low-VOC two-component polyurethane coatings

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CAS Number
28182-81-2
Material Family
Polymers & Resins
At a Glance
Material Family
Polymers & Resins
Record Type
Polymer fluid
Primary Role
Crosslinking / Curing
Functional Roles
Applications & Use Cases
  • Hardener for high-solids, low-VOC two-component (2K) polyurethane coatings
  • Crosslinks hydroxyl acrylic and polyester resins into weatherable, light-stable films with reduced solvent demand
  • High-solids automotive refinish and OEM coatings
  • Low-VOC industrial-maintenance and protective coatings
Safety & Handling
Full SDS available on request

A grade-specific Safety Data Sheet (SDS) — with the complete hazard classification, handling precautions, and transport information — is supplied with every shipment and available on request. Confirm all safety and regulatory details against the SDS for your specific grade.

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Chemical Identity
CAS Number
28182-81-2
Synonyms & Trade Names
low-viscosity HDI trimer low-viscosity HDI isocyanurate high-solids HDI polyisocyanate HDI homopolymer (low-viscosity trimer) aliphatic polyisocyanate hardener Comparable to Desmodur N3600 Comparable to Desmodur N3900 Comparable to Tolonate HDT-LV
Full Description

The low-viscosity grade lets formulators reach high-solids, lower-VOC two-component (2K) polyurethane formulations with less solvent while retaining the weatherability and light stability of the HDI isocyanurate backbone. Crosslinked with hydroxyl-functional acrylic or polyester resins, it produces durable, UV-stable films suited to high-solids automotive refinish and OEM coatings, industrial-maintenance systems and protective topcoats subject to tightening VOC limits. RawSource supplies low-viscosity HDI trimer polyisocyanate in bulk to coating and CASE formulators

Comparable to Desmodur N3600: RawSource supplies this as an independent equivalent (an offset) to Desmodur N3600 — it is a low-viscosity HDI isocyanurate trimer polyisocyanate. It is not genuine Desmodur N3600-branded material, and RawSource is not affiliated with, authorized by, or endorsed by Covestro.

Desmodur N3600 is a registered trademark of Covestro, used here solely for nominative comparison to identify the equivalent grade. RawSource supplies an independent equivalent product; confirm equivalence against your specification and the Certificate of Analysis.

Disclaimer. Information on this page — including properties, identifiers, hazard, transport (DOT/UN) and tariff (HS) classifications, and applications — is provided for general reference and is compiled from authoritative public sources (e.g. PubChem/ECHA, 49 CFR 172.101, the Harmonized Tariff Schedule). Values are typical and are not a guaranteed specification; the Certificate of Analysis (CoA) for the lot purchased governs. Products are sold for industrial and professional use only. Nothing here is a medical, health, or efficacy claim or advice. Always consult the current Safety Data Sheet (SDS) before handling, storage, transport or disposal, and confirm regulatory status, classification and suitability for your application and jurisdiction. Hazard, transport and tariff classifications must be verified for your specific shipment. RawSource makes no warranty, express or implied, and assumes no liability for use of this information. Trademarks. Third-party trademarks and brand names are the property of their respective owners; any reference is nominative — used only to identify a comparable product — and does not imply affiliation with, sponsorship by, or endorsement by the trademark owner.